Fixing Belt Heater Control for Stable Nip Temperature
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face issues with temperature instability in the nip region, leading to potential breakdowns of resistance heating elements and surrounding components due to excessive heating, and inadequate toner fixation resulting in poor image quality.
Innovation Solution
A fixing device with a power control method that includes a first power supply control until target temperatures are reached, followed by a correction control in a second cycle to maintain stable temperatures, using belt and heater temperature detection parts to adjust power supply accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If power is supplied to the resistance heating element to heat the fixing belt, then the fixing belt temperature increases, but the resistance heating element and surrounding parts become excessively heated and may break down
Solution Approach 1:
The patent implements a feedback control system where temperature detection means continuously monitors the fixing belt temperature, and the control unit adjusts the power supplied to the resistance heating element based on this feedback. This closed-loop control prevents excessive heating of the heater and surrounding components while maintaining the fixing belt at the target temperature, thereby resolving the contradiction between achieving sufficient heating and preventing component breakdown.
Solution Approach 2:
The patent stores temperature-related data at predetermined circumferential positions of the fixing belt in advance (during non-fixing operation). During fixing operation, the control unit retrieves this pre-stored data and corrects the power supply to the heating element accordingly. This preliminary preparation allows the system to anticipate temperature variations and adjust heating power proactively, preventing excessive heating before it occurs.
2Reliability
If power supply to the resistance heating element is stopped when the fixing belt temperature exceeds the target temperature, then the heater is protected from excessive heating, but the fixing belt temperature continues to rise due to residual heat
Solution Approach 1:
The patent pre-stores temperature data at various circumferential positions of the fixing belt during non-fixing operation. During fixing operation, the control unit uses this pre-stored information to calculate appropriate power correction values before temperature problems occur. This allows the system to proactively adjust heating power to compensate for residual heat effects, preventing temperature instability without causing excessive heating of the heater.
Solution Approach 2:
The control unit continuously receives temperature feedback from the temperature detection means and dynamically adjusts the power supply to the heating element. When the fixing belt temperature approaches or exceeds the target temperature, the feedback mechanism automatically reduces or stops power supply, while the control unit simultaneously calculates necessary power corrections based on pre-stored temperature data to compensate for thermal inertia and residual heat, thereby maintaining stable fixing belt temperature.
3Temperature
If power supply to the resistance heating element is started when the fixing belt temperature falls below the target temperature, then the fixing belt is reheated, but the resistance heating element may become excessively heated again due to insufficient cooling
Solution Approach 1:
The patent stores temperature-related information at predetermined positions during non-fixing operation as reference data. When fixing operation resumes and the fixing belt temperature drops below the target, the control unit retrieves this pre-stored temperature data and calculates appropriate power correction values. This preliminary preparation enables the system to restart heating with adjusted power levels that account for the heater's thermal state, preventing excessive heating while ensuring the fixing belt reaches the required temperature.
Solution Approach 2:
The control unit monitors the fixing belt temperature and uses feedback from the temperature detection means to dynamically control power supply to the heating element. When the fixing belt temperature falls below the target, the feedback mechanism activates the heater with power levels corrected based on pre-stored temperature data and current thermal conditions. This feedback control ensures the heater is restarted only when necessary and with appropriate power levels, preventing excessive heating while maintaining fixing belt temperature stability.
4Temperature
If the resistance heating element is excessively heated, then the fixing belt reaches the target temperature, but the temperature of the nip region becomes unstable and proper fixing cannot be performed
Solution Approach 1:
The patent employs a feedback control system where the control unit continuously monitors the fixing belt temperature via temperature detection means and adjusts the power supplied to the resistance heating element accordingly. This closed-loop control ensures the fixing belt maintains stable temperature at the nip region, preventing temperature fluctuations that would compromise fixing quality. The feedback mechanism allows real-time correction of heating power to maintain optimal fixing conditions.
Solution Approach 2:
The control unit stores temperature-related data at predetermined circumferential positions during non-fixing operation as reference information. During fixing operation, this pre-stored data is used to calculate appropriate power correction values before temperature instability occurs. This preliminary preparation enables the system to maintain stable temperature at the nip region throughout the fixing process, ensuring consistent fixing quality without temperature fluctuations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Stabilizes the temperature of the fixing belt and heater, preventing excessive heating and component failure, ensuring consistent toner fixation and improved image quality.
Implementation Method 1
the resistance heating element generates heat by the supplied electric power
Implementation Method 2
the fixing belt is heated by receiving the heat from the resistance heating element
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fixing device (7) includes a fixing belt (20), a pressure member (21), a heater (22), a belt temperature detection part (35), a heater temperature detection part (36), and a power control part (8). The power control part (8) executes a first power supply control for supply power to the heater (22), in a first control cycle until the heater temperature detection part (36) detects a target temperature and the belt temperature detection part (35) detects a temperature outside a target range. When the belt temperature detection part (35) detects a temperature outside the target range, the power control part (8) executes a correction control for correcting the target temperature and a second power supply control for supplying power to the heater (22), in a second control cycle 10 times or more the first control cycle.